Cause of one third of all autism cases may have been discovered by scientists

Research in mice suggests increasing levels of a single protein in the brain could reduce symptoms

There is currently no cure for autism, which can result in learning disabilities, mental health issues and other conditions (iStock)

Up to a third of autism cases may be caused by low levels of a single protein in the brain, according to a new study of the condition in mice which could lead to new treatments.

People with autism have been found to have lower levels of the protein, called nSR100, but it was not known whether this was a symptom, a byproduct or the reason behind the condition.

However the researchers found when they reduced the amount of nSR100 in mice, they started to display signs of autistic behaviour. This suggests that having too little of the protein could be a cause of the condition.

Research charity Autistica praised the “interesting” and “high-quality” study, but added more work needed to be done to replicate its findings and gain greater understanding of the link between the protein and the condition in humans.

Professor Sabine Cordes, of the Lunenfeld-Tanenbaum Research Institute in Toronto, said: “We previously reported an association between nSR100 protein levels and autism.

“But this time we show that reduced levels of this protein could really be causative – that’s a big deal.

“Just by reducing the nSR100 levels by 50 per cent, we observe hallmarks of autistic behaviour.”

In the brain, nSR100 acts as a regulator of a process that creates a number of other proteins, which are the key building blocks of cells.

The findings suggest autism is partly the result of incorrectly spliced proteins in brain cells, which could have a number of different effects on behaviour.

Mice genetically engineered to have just half the normal amount of nSR100 displayed signs of autism, such as avoiding social interaction and being more sensitive to noise.

Professor Cordes suggested increasing the amount of the protein in people with autism might help improve their condition.

“Instead of focusing on individual mutations linked to autism, it’s much more powerful to identify regulatory hubs like nSR100,” she said.

“In the future, if you turned this protein up a little bit in autistic patients, you might be able to improve some of the behavioural deficits.”

Dr James Cusack, science director at Autistica, said: “This high-quality research study presents results from an interesting mouse model of autism which are linked to previous research findings in autistic people.

“Further work is required to replicate these findings and understand whether they are specifically related to autism.

“There are many mouse models of autism and it is not fully understood how reliable or valid these are.

“Autism has many causal factors and is related to a number of neurodevelopmental and psychiatric conditions.”

The research was described in a paper in the journal Molecular Cell.